An investigation of the central neural mechanisms of ingestive behavior in terms of the modulation of lateral hypothalamic and lateral preoptic area single neuron activity under simulated conditions of eating and drinking. Also, to determine if suspected central nervous system chemical mediators and other relevant substances such as glucose, NaCl, angiotensin, essential amino acids, and ethyl alcohol affect the synaptic regulatory mechanisms which control the discharge patterns of the cells. Various chemicals will be applied systemically through the peripheral circulation and to individual cells by means of microelectrophoresis.